4-2 Relations and Functions - Math Slide Show

Lesson 4-2 (cont.)
Relation - Any set of ordered pairs
Function - A type of relation where there
is exactly one output for every input. For
every x there is exactly one y.
x y
x y
1 6
1 7
2 7
1
2
6
7
Not a Function
Function - A rule or equation where there is
exactly one output for every input. For every
x-value there is exactly one y-value.
x y x y
x y
-1 -2 -1 2
1 -2
No x- 0 0 No x- 0 0
0 0
value value x-value
1
repeats
2
4
2
4
6
Yes, it is a
function
1
repeats
2
4
-1
1
2
4
6
2
Yes, it is a
function
repeats
1
2
2 4
4 6
-2
1
2
No, it is not
a function
Determine whether the equation is a function.
y
= x
x = y
x y
-2 2
-1
1
0 0
1 1
2 2
input output
-2 0
-1
0 1
1
2
2
Function
x y
2 -2
1 -1
0 0
1 1
2 2
input output
0 -2
-1
1 0
1
2
2
Not a Function
Tell whether the relation below is a function.
1) input output 3) input output
0
-2
1
3
5 Function
2
-1 Function
4
3
0
2) x y
4)
-3 -1
-3 0
Not a
-3 1 Function
-3 2
input output
-2 3
4
-1
5
0 6
Not a
Function
Vertical Line Test - Functions
Vertical Line Test - Functions
y
y
y
y
y
y
y
y
x
x
x
x
x
x
x
x
Function
y
y
y
y
y
y
y
y
x
x
x
x
x
x
x
x
Algebra Slide Show: Teaching Made Easy As Pi, by James Wenk © 2010